1. Field of the Invention
The present invention relates to a socket for an electrical part for detachably holding an electrical part such as a semiconductor device (called as “IC package” hereinlater).
2. Related Art
In a known art, there has been provided an IC socket, as “socket for an electrical part” for detachably holding an “IC package” as an electrical part such as disclosed in Japanese Laid-Open (KOKAI) Patent Publication No. 2002-8809.
The IC package disclosed in this publication includes a number of solder balls, as terminals, which are arranged on a lower surface of the IC package so as to protrude therefrom in an lattice arrangement including vertical rows Y and horizontal lines X.
The IC socket, on the other hand, includes a socket body in which the IC package is accommodated and which is provided with a number of contact pins contacting the terminals of the IC package. The socket body is also provided with a movable (moving) member vertically movable to elastically deform the contact pins so as to be contacted or separated to or from the terminals of the IC package.
The socket body is further provided with a lever member to vertically move the movable member to be rotatable through a rotation shaft, i.e., pivot, and an operation member for rotating or pivoting the lever member is also provided to the socket body to be vertically movable.
By vertically moving the operation member, the lever member is rotated and, hence, the movable member is vertically moved, thus elastically deforming the contact pins, and accordingly, contact portions of the contact pins are contacted to or separated from the terminals of the IC package, respectively.
However, in the conventional structure of the IC socket mentioned above, it is necessary to maintain or ensure contact pressure at the time of clamping the terminal of the IC package and contacting it to a pair of contact portions of each contact pin, and in order to ensure such contact pressure, it has been required for the contact pin to have a relatively large elasticity, and on the contrary, in order to reduce influence between the terminal and the contact portions of the contact pin at the IC packaging insertion time, it is necessary to ensure a relatively large opening distance between the paired contact portions. In view of these matters, when the contact pin having relatively large elasticity is utilized to ensure the predetermined contact pressure, a relatively large operating force is required for ensuring the relatively large opening distance. This matter may cause the device to be inoperative state if the number of contact pins further increases, thus being inconvenient and disadvantageous.